The Amino Acid Requirement of the Growing Chick Fed a Crystalline Amino Acid Diet

Abstract

UNTIL recently, the ad libitum feeding of diets containing free amino acids as the sole source of nitrogen has, without exception, resulted in unsatisfactory chick growth (2.5–4 gm./day), Hegsted (1944), Almquist and Grau (1944), Grau and Peterson (1946), Grau (1947 Grau (1949), Luckey et al. (1947), Benton et al. (1955, 1957). Fisher and Johnson (1957) have recently reported on an improved diet that permits a gain of 6 gm. per day for the first seven days of post hatching. Fox et al. (1958) using the basic amino acid mixture employed by Fisher and Johnson (1956) supplemented with additional amino acids to stimulate the composition of casein, report a gain (calculated) of approximately 7.8 grams per chick per day which over the 28 days of the test equals about one-half the gain that might be expected when diets containing intact proteins of good quality are fed. In contrast, Glista as early…